Skylight venetian blind with improved coaction between the ladders and the slats



g- 1966 H. K. LORENTZEN ETAL 3,265,117

SKYLIGHT VENETIAN BLIND WITH IMPROVED COACTION 1 BETWEEN THE LADDERS AND THE SLATS Filed Dec. 9, 1965 2 Sheets-Sheet 1 FIG.3

J 1 I I l Nam? F 5 g'gfs ph g/awmm 'Mam ATTORNEY Aug. 9, 1966 H, K. LORENTZEN ETAL SKYLIGHT VENETIAN BLIND WITH IMPROVED COACTI BETWEEN THE LADDERS AND THE SLATS 2 Sheets-Sheet 2 Filed Dec. 9, 1963 E 5mm Z Y 0T0 E TM N m m vm X. N H T ISP A in 0 JY B United States Patent Preliminarily it would be well to have in mind certain likenesses and differences between a skylight Venetian blind and the familiar Venetian blind that is used at a vertical window. As regards both types we will consider that the edges of the blind are the margins in which theends of the slats lie and that the ends of the blind are the other two margins of the blind.

Whether for a skylight or for a vertical window, a Venetian blind customarily includes a slat-and-ladder assembly. In such as assembly the slats are spaced along, and are articulated together by, two or more parallel ladders. Each ladder has two longitudinally-extending side-tapes which are interconnected, at each slat position, by either a cross tape or a pair of cross tapes positioned edge to edge.

In a blind for a vertical window the general plane of the blind is vertical. The ladders are suspended from the head or head bar of the blind and carry the entire weight of the slats, which rest on the cross tapes of the ladders. The head-bar structure from which the ladders are suspended includes shiftable elements to manipulate the ladders for tilting the slats of the blind. Usually the head of the blind is provided with a tilt rod on which are mounted tape rolls or rockers, one for each ladder of the blind. The side-tapes of the ladders are so attached to the tape rolls or tape rockers that, upon oscillation of the rolls or rockers by the tilt rod, one side-tape of each ladder is raised and the other side-tape of each ladder is simultaneously lowered, thereby tilting the slats of the blind. However, blinds have been made in which one side-tape of each ladder remained stationary while the other side-tape of each ladder was either raised or lowered to tilt the slats of the blind. At the bottom of a blind for a vertical window there is ordinarily a bottom bar to which lift cords are attached for raising the bottom bar and accumulating the slats of the blind on top of it.

In a skylight Venetian blind the general plane of the blind is either horizontal or inclined to the horizontal, rather than being vertical. The ladders extend in the general plane of the blind and carry little or none of the weight of the slats. The support for the slats is provided by tracklike members which extend for the length of the blind and on which the slats rest. The ladders establish the slat spacing and articulate the slats together for tilting. In a skylight blind there is no bottom bar; there are ladder-controlling means at both ends of the blind, and to which the ends of the side tapes of the ladders are attached. The ladder-controlling means at one end of the blind may be a driver, similar to the tilter, tilt rod and tape rolls of a Venetian blind for a vertical window. The ladder-controlling means at the other end of the blind may be a follower, having a tilt rod and tape rolls but no tilter.

In the interest of low cost and availability of materials, the ladder material used in skylight Venetian blinds is at least of the same type and the same construction as the commercial ladder material that is used for Venetian blinds for vertical windows. For use in skylight blinds, we considered that the best commercially available type of ladder material is so-called plastic ladder materialoften referred to in the trade as ladder tape or simply as tape. This is available in so-called single ladder style and so-called twin ladder style. We use the twin ladder style; it has, at each slat position, two cross tapes that are positioned edge-to-edge. While we may use the identical ladder material that is used for blinds for vertical windows, we prefer that the cross tapes be somewhat Wider than in the twin-ladder style plastic ladder material that is customarily used in blinds for vertical windows.

The longitudinal tapes of plastic ladders are of soft flexible plastic material in which is embedded strands that render the longitudinal tapes substantially nonstretchable in a lengthwise direction. The cross tapes are of soft flexible plastic material, without embedded strands. Skylight Venetian blinds made with such plastic ladders of twin ladder style have functioned satisfactorily when first installed and thereafter have often failed to properly tilt some or all of the slats of the blind. The reasons for such failure are not clear to us and it may be that the reasons are different in different instances. However, some probable reasons will be mentioned hereinafter in connection with the description of our invention, the general object of which is to overcome the malfunctioning of skylight Venetian blinds in respect of the tilting of the slats.

Among other objects of the invention are to provide a skylight Venetian blind, made with the usual components including plastic ladders, which has a very high degree of reliability as regards tilting of slatseven when the blind has been used for a long period of time in a location that subjects the blind to relatively high temperatures.

Among further objects of the invention are (a) to provide an attachment for the ladders of skylight Venetian blinds to obviate malfunctioning in the tilting of slats, (b) to provide such an attachment which is simple and which can be facilely applied to the ladders and (c) to provide such an attachment which can be inexpensively manufactured on a quantity-production basis.

ther objects and advantages will be apparent from the detailed description hereinafter.

In both the description and the claims, parts at times may be identified by specific names for ready reference and understanding, but such nomenclature is to be understood as having the broadest meaning consistent with the context and with the concept of our invention as distinguished from the pertinent prior art. The best mode in which we have contemplated carrying out our invention is herein disclosed and is illustrated in the accompanying drawing forming part of this specification. Except as may be other-wise indicated the description refers to the specific form of the invention shown in the drawing; it does not necessarily refer to any other form in which invention may be embodied. The claims, however, do embrace other forms in which the invention may be embodied.

FIG. 1 (Sheet 1) is a diagrammatic isometric view showing an installed skylight Venetian blind.

FIG. 2 (Sheet 1) is an isometric view showing our attachment, as manufactured and before being afi'ixed to a ladder of the blind.

FIG. 3 (Sheet 1) is a fragmentary isometric view showing diagrammatically the attachment of FIG. 2 attached to a cross tape of a ladder of twin ladder style.

FIG. 4 (Sheet 2) is a fragmentary diagrammatic view looking from the line 4-4 of FIG. 1. To simplify the figure the cross tapes on the convex sides of the slats are omitted.

FIG. 5 (Sheet 1) shows a fragment from FIG. 4, on a larger scale. The cross tapes on the convex sides of the slats are included.

'FIG. 6 (Sheet 2) is a diagrammatic view which is the 3 same as FIG. 4 but with the slats of the blind in open position, the cross tapes on the convex sides of the slats being omitted.

in FIG. 1 a skylight Venetian blind designated as a whole by is installed in a skylight opening designated as a whole by 11. The opening is provided with a closure designated as a whole by 12, which includes a transparent pane or bubble 14.

Sheetsteel channels and 16 are disposed horizontally and are afiixed, respectively, to the sides 11a and 11b of the opening 11. At one end of the opening 11 there is a sheet-steel head or head-bar 25. The ends of the head-bar 25 are nested into the channels 15 and 16 and secured thereto as by sheet-metal screws, two of which are at 25', 25'. At the other end of the opening 11 there is a similar head-bar 35, the ends of Which are similarly secured to the channels 15 and 16.

The space that is bounded by the channels 15, 16 and the head-bars 25, 35 is occupied by a slat-and-ladder assembly which is designated as a whole by 21. The slats 17 are of roll-hardened sheet metal, either aluminum or steel. We use aluminum slats approximately .010" thick. The ends of the slats are nested into the channels 15 and 16 and rest upon the longitudinal inturned beads 15' and 16' of these channels. These beads constitute tracks or rails that carry the weight of the slats. All of the slats are articulated together by ladders 18, 19 and 20, of which ladders 18 and 19 are positioned toward the end of the slats and ladder 20 is at the midpoint of the length of the slats.

The metal head or head-bar is substantially the same as is used for blinds for vertical windows, being tipped on its side and provided with a different operating connection to turn the tilter. The head-bar 25 includes a sheet-steel channel 26, two braces 26' that extend across the open side of the channel, a tilt rod 27, three tape rolls 28 mounted on the tilt rod, and a tilter 29 for oscillating the tilt :rod. The two side-tapes of each ladder 18 are attached to one of the tape rolls 28 in customary manner so that, upon oscillation of the tilt rod 27, the ladders are manipulated in customary manner for tilting the slats of the blind.

The head bar or head 25 may be of conventional construction such as, for example, the construction shown in US. Patent 2,629,434, the head bar being turned on its side and the tilter pulley of that patent being replaced by a platelike member 30 having a hole through which the end of a window pole can be inserted to turn the tilter. The tape rolls 28 are conventional and may be as shown in US. Patent 2,629,434 or as in US. Patent 2,831,536.

The head 25 constitutes controlling means for the ladders, at one end of the blind. This controlling means is a driver which manipulates the ladders for tilting the slats. At the other end of the blind the head constitutes controlling means which is a follower that follows the movements imparted to the ladders by the head 25. The head 35 is the same as the head 25 except that it faces in the opposite direction and has no tilter 29.

FIG. 2 shows an attachment which we attach to some of the cross tapes of the ladders 18 and 19. This attachment is made from a single piece of thin sheetmetal that has been roll-hardened. As manufacturer, the attachment 40 is a V-shaped trough having walls 41 and 42. Tabs 42a and 42b extend from the free edge of the fall 42. We manufacture the attachment 40 from rollhardened aluminum slat stock about .008" thick. This is the same slat stock that is used for making the slats 17 of the blind except that it is approximately .002" thinner. While the attachments 40 have substantial rigidity and springiness, they are bendable to afiix them to cross tapes of the ladders.

At each slat position the ladders have a pair of cross tapes that are positioned edge-to-edge. FIG. 3 shows a short length of ladder 18 or 19 and the pair of cross tapes C and C at one slat position. Aflixed to the cross tape C is one of the attachments 40. In affixing the attachment 40 the trough-shaped piece of FIG. 2 is positioned astride of the cross tape C with one longitudinal edge of the cross tape in the bottom of the trough formation. Then the trough formation is collapsed into close priximity with the faces of the cross tape C and the tabs 40a and 40b are folded against the opposite wall of the member 40.

The height of the trough formation of the member 40 is substatinally equal to the width of the cross tape C Thus, when the member 40 has been applied as in FIG. 3, it constitutes a sleevelike member which embraces the cross tape C In the operation of the blind the attachment 40 acts mechanically as a strut and to a lesser extent as a tie, as will be explained. For this reason We designated it as a strut-tie.

The slats are so threaded through the ladders that one cross tape of a pair is on the convex side of the slat and the other cross tape of the pair is on the concave side of the slat. In associating a strut-tie 40 with a slat, we ordinarily place it on the cross tape which is on the concave side of the slat; see FIGS. 4-6. However, it may be placed on the cross tape which is on the convex side of the slat, if tight closure of the slats is not desired. If we provide ladder 18 with a strut-tie member 40 at a particular slat, we also provide ladder 19 with a struttie member at the same slat. By trial and error we have found that, with a well-made skylight blind of good construction, malfunctioning in respect of tilting of the slats is obviated by associating the strut-like members 40 with the third slat from the driver head 25 and every third slat thereafter, the struttie members being provided for each of ladders 18 and 19 and being placed on the cross tape which is on the concave side of the slat.

In the usual vertical blind for a window the slats are supported by the ladders themselves and little or no lifting of the weight of the slats is involved in the tilting of the slats. Referring to FIG. 4 it will be seen that the slats are supported by rails or tracks such as bead 15' and to tilt the slats from the closed position of FIG. 4 to opened position of FIG. 6 required the lifting of the Weight of the entire array of slats by a distance approximately equal to half the width of a slat. Additionally the lower edges of the slats scrape along the supporting rails by a distance approximately equal to half the width of a slat. Thus in opening the slats of a skylight blind the ladders have to perform very heavy duty as compared to opening the slats in the usual blind for a vertical window. Having in mind the flexibility of the longitudinal tapes of the ladders and the flexibility of the cross tapes of the ladders, the heavy duty required of the ladders in a skylight Venitial blind could be expected to lead to malfunctioning. Moreover, skylight blinds are at the top of the room and often receive direct sunlightwith the result that at times they may be at a temperature of 120 F., or even more. With the slats open as in FIG. 6 the slats are supported by the underlying rails (e.g. 15) and the slats in turn support the upper longitudinal tape 18a of the ladder. The weight of lower longitudinal tape 18b hangs on the cross tapes and may possibly lengthen them when they are unduly warm. Moreover, in the usual skylight blind the manipulation of the ladders to open the slats tends to tension certain of the cross tapes at times; and this can lengthen those cross tapes when they are unduly warm.

Our strut-tie members 40 act as mechanical ties. With the lower longitudinal tape 18b thus supported at every third slat, the weight of lower longitudinal tape 18!) isnt available to substantially lengthen the cross tapes when they are warm. Moreover, when the ladders are operated to shift the slats from the FIG. 4 position to the FIG. 6 position our strut-tie members 40 act as struts which force the two longitudinal tapes apart. This makes it easier for the ladders to tilt the slats and protects the cross tapes against undue tensioning during the tilting of the slats.

Regardless of the factors which may be involved, we have found by actual experience that our strut-tie members used as above set forth obviate the malfunctioning. The tie action required of our members 40 is small and is afforded by light frictional engagement between the members 40 and the cross tapes which they embrace.

As is perhaps best seen in FIG. 5 our strut-tie members 40 substantially span the slats, being a little shorter than the width of the slats. We position the cross-tie members offset with respect to the longitudinal center of the cross tapes, with the lower ends of the members 40 close to or even against the lower longitudinal tapes and with the upper ends of the members 40 at an appreciable distance from the upper longitudinal tapes. This insures that the strut-tie members wont interfere with full closing of the slats by projecting between the upper edge of a slat and the face of the subjacent slat against which.

such upper edge is to close.

We have made our blinds of various sizes and with various ratios of length to width. Some of our skylight blinds have been as much as 5 feet long, and some have been as much as 8 feet wide.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A skylight Venetian blind comprising:

a slat-and-ladder assembly in which (a) the slats are crowned, (b) the ladders have. flexible side tapes, one side tape of each ladder being above the slats and the other side tape of each ladder being beneath the slats, (c) the ladders have pairs of flexible cross tapes distributed along the lengths of the ladders and interconnecting the side tapes thereof, and (d) the slats are threaded between the cross tapes of the pairs of cross tapes so that one cross tape of a pair is on the convex side. of a slat and the other cross tape of the pair is on the concave side of the slat;

rails on which the slats rest and which support the weight of the slats;

ladder-controlling means at the two ends of the blind,

the end-portions of the side tapes being fastened to the ladder-controlling means, and such controlling means including means to operate the ladders to tilt the cross tapes thereof to various angles for varying the tilt of the slats;

and strut-ties distributed along the ladders and affixed to cross tapes thereof,

said strut-ties spanning the widths of the slats,

at least substantially,

and the strut-ties being flexibly connected to the side tapes by the cross tapes to which the strutties are aflixed.

2. A skylight Venetian blind as in claim 1 in which the strut-ties are aflixed to cross tapes which are on the concave sides of slats.

3. A skylight Venetian blind as in claim 1 in which the strut-ties are sleevelike and embrace the cross tapes to which they are afiixed.

4. A skylight Venetian blind as in claim 2 in which the strut-ties are off-center with respect to the lengths of the cross tapes to which they are affixed, the direction of off-center being toward the lower side-tapes of the ladders.

5. A skylight Venetian blind as in claim 1 in which strut-ties are associated with only nonconsecutive slats of the blind.

6. A skylight Venetian blind as in claim 5 in which each slat that has a strut-tie associated with it has at least two strut-ties associated with it, one toward one end of the slat and the other toward the other end of the slat.

7. A skylight Venetian blind as in claim 1 in which each strut-tie consists of a piece of thin roll-hardened sheet-metal, overlying the faces of the cross tape and bent into close contact therewith.

8. A skylight Venetian blind as in claim 7 in which the sheet metal is aluminum and is a piece of Venetian blind slat stock.

9. A Venetian blind ladder comprising: a pair of flexible side tapes, a series of flexible cross tapes interconnecting the side tapes, and strut-ties on certain of the cross tapes, each strut-tie being composed of a troughshaped piece of sheet metal positioned astride of the cross tape with one edge of the cross tape in the bottom of the trough formation, the length of the trough formation being somewhat less than the length of the cross tape, and the trough formation being collapsed into close proximity to the faces of the cross tape and making frictional engagement therewith.

10. A Venetian blind ladder as in claim 9 in which the two sides of the trough formation are planar and the depth of the trough formation is substantially equal to the width of the cross tape.

11. A Venetian blind ladder as in claim 9 in which the strut-tie is provided with at least one tab extending from the free edge of a wall of the trough formation, and the tab is folded over and positioned against the opposite wall of the trough formation.

12. A Venetian blind ladder as in claim 9 in which the struttie is provided with two tabs, one toward each end of the trough formation, and each tab extends from a Wall of they trough formation and is folded over and positioned against the opposite wall of the trough formation.

References Cited by the Examiner UNITED STATES PATENTS 631,284 8/1899 Ellison 24-1151 723,762 3/1903 Tumler l60176 X 2,738,558 3/ 1956 Davis 20-62 3,170,505 2/1965 Lorentzen et a1 176 FOREIGN PATENTS 143,336 l/ 1931 Switzerland. 365,863 1/1963 Switzerland.

HARRISON R. MOSELEY, Primary Examiner.

P. M. CAUN, Assistant Examiner. 

9. A VENETIAN BLIND LADDER COMPRISING: A PAIR OF FLEXIBLE SIDE TAPES, A SERIES OF FLEXIBLE CROSS TAPES INTERCONNECTING THE SIDE TAPES, AND STRUT-TIES ON CERTAIN OF THE CROSS TAPES, EACH STRUT-TIE BEING COMPOSED OF A TROUGHSHAPED PIECE OF SHEET METAL POSITIONED ASTRIDE OF THE CROSS TAPE WITH ONE EDGE OF THE CROSS TAPE IN THE BOTTOM OF THE TROUGH FORMATION, THE LENGTH OF THE TROUGH FORMATION BEING SOMEWHAT LESS THAN THE LENGTH OF THE CROSS TAPE, AND THE TROUGH FORMATION BEING COLLAPSED INTO CLOSE PROXIMITY TO THE FACES OF THE CROSS TAPE AND MAKING FRICTIONAL ENGAGEMENT THEREWITH. 